The Great Gaster
by SodaFiz
Summary: Few know the tale of the great Gaster. There are so many unanswered questions: Just how was Gaster erased from existence? How exactly is he related to Sans and Papyrus? There was only one who witnessed and knew the truth firsthand: that it all started with a simple human. (An Undertale/Great Gatsby inspired story)
1. Royal City

**This story is exactly how the description states: basically a style with the basic plot of The Great Gatsby with Undertale characters. It's not an exact AU, but I guess it technically could be called one.**

 **i got this idea after my best friend jokingly called Gaster "The Great Gaster" in reference to The Great Gatsby and as a result this story was born. It'll contain a few OCs, but of course it's centered a lot on Gaster, too. It'll contain quite a few people that are, in a way, my Undertale equivalents of characters in The Great Gatsby. A couple are obvious. Others... maybe a little hard to distinguish. Can you guess who's equivalent to who? :)**

 **Just FYI, this isn't going to have the same exact plot as The Great Gatsby. I'm taking a few creative liberties with it because I want this story to also be unique. Some character personalities might be different than those of the TGG. It's intentional because I want my characters in this story to be likable. It's also not going to have a lot of the current UT characters because it's about Gaster so it takes place before Frisk and the others. However, that doesn't mean other characters won't show up as the story progresses in its timeline ;)**

 **Anyway, please leave a review! It might not seem like much at first, but I have great plans for this story, especially during the middle and end. It'll also answer a lot of questions about Gaster like how he got erased from time, etc.**

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 **Chapter 1: Royal City**

My father once told me, "Whenever you feel like criticizing someone, just remember that you haven't experienced what they've experienced. Instead of scorn, try to understand where they're coming from." This is a statement I've tried to hold myself to. I like to think I'm a good man, but I admit that I, like anyone, am not without fault.

Sometimes I wonder if I had been too passive concerning my friend Gaster. He was a brilliant man, er… skeleton, but like myself and others he was not without fault.

I miss him though. He was one of the few friends I had. However, it didn't start out that way.

But before I go into a whole spiel of my friend Gaster, I suppose I should provide some background on myself.

My early childhood was happy. I grew up in a little house in a small family just outside Snowdin. I displayed an early interest in science, a passion my parents encouraged me to pursue. My family's household consisted of my mother, father, younger brother, and myself. I was the eldest child.

We were a small family of rather wide-eyed humanoids, at least that's the best description I can think of. As I child I barely knew what humans were, but now I know exactly what a human looks like and have come to realize humans and my family were not too different biologically. We stood and walked on two legs; we had two arms, two hands, and two feet. At first glance it almost seemed like we weren't that different, but there were differences.

The species of monster I was did not have hair and our skin was very different texturally. Human skin is so smooth and fragile, easily damaged. Our skin was smooth, but tougher. I didn't have scales like the reptilians, but I wasn't so delicate, either. Our eyes were also much wider than a human's, as well as perfectly round. We weren't generally inexpressive, but we often looked that way. In fact, other monsters have humorously called me a master of the "blank look." I find it amusing because it's true.

My whole immediate family was orange in color except myself. I was a golden yellow, a trait apparently inherited from my grandfather.

Though my childhood was happy, I can't quite say the same for about half of my teenhood. My parents died when I was fourteen and my brother only six. We were then placed in foster care. It wasn't bad, but it couldn't be called fantastic, either. When I reached early adulthood, I found it a silly idea to continue living with my guardian, so I actively searched for a job and a place of my own.

It was an unusually warm day for Snowdin when I spotted an ad in the local newspaper stating that the royal scientist W. D. Gaster was looking for a helper. "Must be interested in and show potential for a future career in scientific endeavours," I read. "Any previous background in science is a plus, but not absolutely necessary. Any monster of any status can apply."

A warm wave of excitement passed through me and a whirlwind of questions filled my mind. _THE Gaster? Gaster the royal scientist? He's looking for help? And anyone can apply?_

I didn't idolize Gaster as much as some, but I did have a great admiration for him. He'd been talking about building some type of machine that if successful, might revolutionize electricity for us monsters. Few details were released, but if I remembered correctly Gaster had said it could bring electricity to every monster house in the Underground. I had studied electricity and loved the idea of it, but alas I didn't have it growing up.

I couldn't help but feel I may have a good chance at this job. Few monsters had scientific ambition in the Underground. There was only _one_ royal scientist after all, and that was Gaster. The only monster I even knew about with a passion for science was myself. I had read every science book in the Snowdin library at least five times, maybe more. I even liked to consider myself an amateur scientist, though I had held no official job with that title, or any title really.

 _I might actually have a chance,_ I couldn't help thinking rather confidently, so I got to work. I filled out an application and sent it to the royal palace through the mail. I waited anxiously several days, answering the door every time the doorbell rang. My brother often watched me in amusement.

It was maybe two weeks later when I received a response. I snatched the letter out of the postman's hands, perhaps a little too roughly, and ripped it open.

My normally neutral expression wasn't passive at all. A grin was gracing my features as I read over the letter. "What's gotten you all smiley?" my brother asked from his seat on the couch.

"I was called in for an interview. _Next week,_ " I murmured. I eyed my brother. "Just think," I began. "I'm going to meet Gaster himself."

"Nice," replied my brother absentmindedly. He wasn't really paying attention now, but I didn't care. I rushed into the room I shared with my sibling and frantically began to write a reply letter.

The next week twenty-four-year-old me was making the trek through the Underground to the royal castle. As always I first travelled through Snowdin, my homely little town. I shivered and pulled my coat closer, my feet crunching cross the snow. The air smelled like cold and snow, a smell I was very familiar with. It was snowing the day I left, not unusual at all. I had already bid goodbye to my brother and guardian.

My guardian was a kindly, middle-aged woman who cared deeply for me and my brother. She was a small, brown, rabbit-like monster. Though I was fond of her, I coudn't say I loved her like a mother or even an aunt. I doubt my brother did either, but I never asked, so I never knew for sure. My guardian was sad to see me go. She guessed I would be moving away if I got the job. I bid her goodbye a little sorrowfully but without any tears, hoping this would mark the next stage in my life.

I left Snowdin and entered Waterfall. The air turned from dry and cold to humid and just slightly chilly. A little sweat gathered on my forehead, so I unbuttoned my jacket. At first Waterfall was open with only a few small streams I had to walk over, but I soon found Waterfall had a cave system I had never encountered before.

The pathways grew dark and damp. I huddled closer into my jacket, not for warmth but more a sense of security. I had heard of the other Underground areas like Waterfall and Hotland, but as a child I barely left Snowdin. I had never been much of a traveller. At the present time I desperately wished I had thought to bring a map or at least ask for directions. _Foolish,_ I scolded myself.

The caves had begun to make me feel claustrophobic. My journey started out wondrously. I had even passed a mysterious piano and an old set of armor singing a haunting melody. I wondered if the rain might have been hitting the metal in such a way that it sounded like music. Waterfall wasn't exactly giving me a great sense of security, however, so I didn't bother to investigate.

The cave system was like a dark maze. Crystals of blue and purple, probably lit by magic, dotted the pathways. The air was damp and stale, not exactly comforting. I tried to pay attention to specific patterns of crystals and directions of the passageways, but I was sure I kept going in circles. I managed to find a tiny town called Temmie Village. They were curious little creatures, a little like cats with hair, but not very intelligent. I asked them for directions, but they didn't seem to know how to get to Hotland. Sighing, I politely gave my leave and ventured back into the caves.

Hours must have passed that I didn't see a sign of anyone. My passive expression took on one of dread. Would I ever leave this place? Fed up, I groaned and sat back against the glowing wall. Using my logical mind, I considered my options.

Option one, wait for someone to find me. _Not likely._ Option two, search for a way out again. _I've been doing that for hours._ Option three, try to find my way back to Temmie Village. _That seems the most plausible…_

A sudden clink of something jerked me from my thoughts. Looking up, I craned my head to one side, listening for sounds. It clinked again. _Sounds like metal,_ I thought. _And voices._ Excited, I sprang to my feet and hurried towards the sound. The crystals flew by like whizzing trails of blue light.

Three dark, yet silvery figures came into sight. They were talking to each other. There were two tall figures and a short one. The short figure walked very upright with its chest held high, giving off an air of importance. I guessed it was the leader.

Said figure caught sight of me quickly and suddenly stopped. Two green glowing… claws or… something, had appeared at its sides. They were like hands, but floating detached from the small figure's body. They stopped the figures following the short one and pointed at me. "Who are you?" demanded the small figure. "Speak."

I stood as tall as I could, not easy for someone like me who was just over five feet. "My name is Fidel… Fidel Amin," I stated. "I'm trying to find my way to the royal castle in… the Royal City." I suddenly realized how silly that name sounded. _Wouldn't the king want to name it something more… astounding?_

The figure's head twitched once and began to step towards me. Making its way to me, I finally got a clear look at it in the glowing light of the crystals. "Fidel… I know that name," remarked the voice. As the figure stopped in front of me I realized both its voice and figure were feminine. She was dressed in black under armor with silver plating over her chest, head, and lower legs. She didn't appear to have arms and I suddenly realized that those glowing green claws must have been her magical version of hands. Wide strings of metal hung from her waist and clinked against her legs as she walked, almost like an armored version of a skirt. Her visor on her helmet suddenly glowed green and flipped upward, revealing a pale green face with a small snout.

The woman was almost exactly my height. Her eyes had a friendly but serious look. She almost had a reptilian or maybe a dinosaur-like figure, but she stood straight upright like I did. "Ah, I remember that name," she asserted. "You're the Fidel who applied for position of helper to the royal scientist, aren't you?"

I nodded. "Yes."

She suddenly extended a green, magical claw in greeting. I shook it slowly. "I'm Sasha, captain of the Royal Guard," she said, studying me intently. "So, if you're supposed to be in Royal City, then what are you doing way out here?"

My face flushed. "Well... I got lost trying to find the Royal City."

She raised a brow. "Why didn't you just take the river ferry?"

"River taxi?"

She frowned. "You know, the ferry that the River Person runs. They gives rides to anyone who needs to travel quickly from town to town. The river runs all through the Underground, so it's perfect for speedy travel."

I found myself staring at the ground. "I've never heard of it before," I confessed. I imagined my cheeks were colored in embarrassment. "I'm not much of a traveller."

Captain Sasha eyed me with amusement. "I'm guessing if you don't even know about the ferry, then you don't know where you are, do you?"

I shrugged my shoulders. "I know I'm in Waterfall."

She chuckled and shook her head. "In that case, I will lead you to the city." She turned to the two figures behind her, who were completely covered in armor from head to toe, and spoke to them. "Buck! Arlo!" she commanded with an air of confident authority. "Make your way to the city on foot. All four of us won't be able to fit on the ferry together and I know you're familiar with way back. I'm going to lead Mr. Amin back to the castle myself. He needs to know about the river ferry if he's going to be travelling around the Underground." Her slitted visor flashed green a second time and slid down over her eyes. Her face was now obscured from view completely.

The two guards, Buck and Arlo I presumed, obviously respected their captain. They bowed and cried, "Yes, ma'am!" before sauntering off.

I was soon left alone with the captain, who gestured me in the opposite direction. "Come," she commanded with pleasant seriousness.

She led me through the caves without hesitation. I let out a quiet sigh of relief. _Now I have someone who knows where she's going._

We began to descend down a dark passageway and I heard the faint sound of rushing water. The wall crystals soon disappeared and the passage grew more narrow. We walked only several yards before the air turned damp and the rocky ground beneath my feet was slippery with moisture. I almost lost my balance over the wet rock, but managed to regain my composure. Captain Sasha, however, seemed to have no trouble walking. I observed three long claws poking out of her shoes. They were a greenish tint like her skin, so I assumed they were natural. _Perhaps they help with grip,_ I concluded. _Either that, or she's just experienced walking over wet ground._ Unless I asked, I wouldn't know for certain and at the time I wasn't feeling up for conversation, so I remained silent.

The passageway suddenly ended and I almost plunged forward into rushing water. Luckily the captain's "magical claw," as I had dubbed it, grabbed onto my jacket. Yanking me backward, the captain chuckled at my clumsiness.

"Tra la la. Don't fall in," sang a voice in front of me. I turned to see a cloaked figure studying us. Its face was completely dark and obscured beneath its hood. I saw no mask or visor that it might have worn. It was like the figure didn't have a face at all. "Where to?" it asked cheerfully.

"The Royal City," answered the captain. She bobbed her head politely, as if paying it a respect.

The River Person nodded. "Step in."

Captain Sasha let me step on first and she stationed herself behind me. It was a narrow fit, but we were both quite small, almost the same size. I was just slightly thinner, though I doubted I was anywhere near physically fit as she was.

The wooden boat, much like a small canoe, rowed steadily forward. "Tra la la. I am the riverman," sang the the hooded figure in front of me. "Or am I a riverwoman? Oh, it doesn't matter. I just love to ride in my boat. I'm happy to share my boat with others, too. Tra la la. Why don't you sing with me?"

The captain began to hum along with the River Person's tune. This hooded person had a sort of charm to them. I couldn't help smiling at the person's cheerful nature, whoever they were. I found myself humming along to their happy melody like the captain behind me was.

After a steady, peaceful ride that left me feeling quite serene, we arrived at the Royal City. "Tra la la, goodbye for now." The River Person waved farewell.

The city was breathtaking. Towers upon towers of buildings surrounded me, all bright in color. I was a small man and the buildings made me feel just miniscule. It wasn't the most brightly lit, but the city itself almost had a glow of its own. Monsters of all shapes and sizes busied about, buying supplies from shops and rushing to places who knows where. In the distance stood a magnificent palace that towered over the city itself. I felt smaller than ever.

Captain Sasha watched me with amusement. "It's amazing, isn't it?" she said.

I breathed in deeply. "Yes."

"Most monsters have been to the Royal City at least once in their life," remarked the captain. "It's rather funny to watch an adult man come to this place for the first time in his life."

I frowned. "I hardly ever traveled when I was younger."

The captain shrugged, or at least implied it, considering she had no arms. "Anyway," she continued. "We need to get to the palace. I believe that's where Gaster and the king are going to interview you."

We hurried off. The palace grew steadily larger as we approached, towering over us even further. The gate was opened and the captain stepped forward. A tall, heavy monster stepped into the courtyard and the captain bowed before him. I gasped, suddenly realizing I was standing before King Asgore himself. I immediately dipped my head in a bow. As I did so, I glimpsed a figure of… something behind the goat king. It was tall, thin, and strikingly dark with a white face. _Could it be…?_ I wondered. Still bowing, I glance up further, but by the time I got a direct look, the figure was gone.

A deep chuckle met my earholes. "You can stand up. No need to be so formal," said a kindly voice. It was the king. "Welcome, you two. Sasha, who is this man?"

Captain Sasha stood up and I followed her example. "This is Fidel Amin," she stated. "He's the one you scheduled to interview today."

The king's face brightened. "Wonderful!" he exclaimed before turning to me. My naturally wide eyes grew even larger. The king was addressing _me?_ "Mr. Amin," said Asgore with a bright smile. "Come on in. I'm so glad you've arrived. I'm sure Mr. Gaster is eager to meet you."


	2. The Interview

**A/N: I am SO GLAD to finally get the second chapter out. It's shorter and a bit slow, but don't worry! The main story will start to pick up in the next chapter. For now, a big thank you to the people who have followed, favorited, and reviewed. It has given me determination to finish this chapter and eventually the rest of the story! Enjoy!**

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 **Chapter 2: The Interview**

Dr. Gaster was taller than I imagined. His height rivalled Asgore's, though I doubt he would have won in a duel of brute strength.

The captain had left me in the care of Asgore, who led me into a large study room. A single lantern was a lit on the desk, casting a dim glow about the rows and shelves of books lining the room. A lone figure was standing at the edge of the desk. Very tall and thin, he stood draped in a long black coat. Underneath the figure's coat was a beige turtleneck sweater. The figure's face was white and skeletal.

Asgore waved me forward with a kind smile. "This is Dr. Gaster," he introduced. "We're both very eager to see what talent you might show for the job."

I extended my hand toward the doctor. He took it gently but firmly, his eyes studying me. Like I expected in a skeleton his eye sockets were dark, however, they had soft white pupils that gave him a friendlier appearance. All monsters were held together by magic, but we still had a form of flesh that gave us some of the same organs a human has. I had fleshly pupils held in place in my eye sockets like most monsters, but I wasn't so sure about a skeleton. In fact, I had never even encountered a skeleton monster until this moment. Skeletons didn't have real eyes or so I had heard. My best guess was that his own pupils were possibly a pure form of magic manifested visibly in his eye sockets.

"Sit down," said the doctor. His voice was on the deeper side and not very stern, but still expectant. His curious expression quickly took on one of professionality and business.

Just a tad nervous, I seated myself in the chair across from Dr. Gaster who seated himself on the other side of the desk in a chair opposite mine. The king plopped into a nearby couch. His large form took up more than half the sofa. I wanted to smile in amusement, but refused to during a situation of seriousness such as this.

"Let's get down to business," said the doctor nonchalantly, pulling out a clipboard and a pen. He turned to look at me and I suddenly felt small under his gaze. "Your name?"

"Fidel Amin, sir." I silently gulped. _Had I been too formal?_

The skeleton raised his brow ever so slightly, but continued calmly. "How long have you studied science?"

"Well, I've been interested in science since I was a child, but I began to study it more in depth when I became a teenager."

"What areas have you studied?"

"A little bit of everything, I suppose. I've studied biology, physics, mathematics, and a little chemistry."

"Do you have any experience in engineering?"

I frowned. "Well, I've read over its basic principles, but I haven't studied it much other than that."

It was the doctor's turn to frown. He leaned back in his chair and twiddled his bony fingers. I found myself fiddling with the edges of my shirt. Puckering my lips ever so slightly, I wiped my forehead with my hand. A slight moisture coated my palm. Nerves. _What perfect timing to get anxious during a job interview,_ I thought, trying to keep my face blank. I was skilled at that, but perhaps it was just a tad more difficult when I was nervous I might have upset my potential future employer.

"Why do you think you are qualified for this position?" The doctor's sudden question almost made me blanch. Here he was pondering my engineering experience when he suddenly switches topics. Alright.

"Well, I..." Breathing deeply, I made myself resume a serious expression not too different from my neutral one. I forced my continuing words out as steadily as I could. "I have a passion for science and I've studied every single book containing science in my local library for about a decade now. I am aware that science can be difficult, but I'm willing to work hard. I want to gain experience in any scientific field that I can. I want to make scientific advancements. I want..." My voice trailed off and I almost flushed. I had started to ramble.

The doctor and Asgore`both waited patiently for me to finish, but I found no words to continue. A few seconds ticked by. Asgore cleared his throat and I shifted uneasily in my chair.

Doctor Gaster suddenly stood up and turned to the king. "Your Majesty, may I talk to you out here?" He was pointing to the door.

My naturally wide eyes widened even more. The king and the doctor slipped outside and closed the door quickly, leaving me alone in the study. I let out a small groan. _Did I blow my chances?_ I wondered, tapping my fingers nervously against the comfortable armchair I sat in.

As I waited my eyes trailed across the room. It was a very large, grand-looking study. I eyed one set of shelves. It was devoted to books of monster history. I scanned another, which contained a row of monster anatomy. Glancing at all the shelves, I was in awe. Not only did Doctor Gaster have at least four or five times the amount books the Snowdin "Librarby" (that misspelling always annoyed me) had, but these bookcases held books of history, mathematics, engineering, biology, chemistry, physics, and even literature on humans. I merely glanced over the human books, but the quantity of science and monster history books almost made me drool. Chuckling at such a childish sentiment, I quickly shut my mouth with a silly smile.

I jumped as the door suddenly opened and Dr. Gaster shuffled in followed by Asgore. The skeleton marched over to his desk without giving me a second glance and began to rifle through a stack of papers with an expression of determination. The sheets crinkled and rustled as he leafed through them. With a small grunt he pulled out small stack of paperclipped pages and slapped it on the desk in front of me. "What do you make of this?" he asked quickly.

Careful not to bend the stack, I scanned its pages. At first glance I thought it was just a math worksheet, but after reading it through a second time I realized it was actually several pages of mathematical equations and diagrams. Numbers and shapes stared back at me. They were all arranged in certain orders, many of them patterns. All written by hand, these papers were like a clash of algebra, geometry, trigonometry, and calculus. If anything, the pages looked like a plan for some type of project. Shapes were drawn to represent spaces of… something, and there were no units following the numbers, so I wasn't sure what these calculations might apply to. Nothing was labelled except with numerical units. Was this a stack statistics in mid-calculation? A plan for a building? My mind whirled. It could have been anything!

And yet, something caught my eye in one of the calculations. It was just a simple equation of numbers, but it used a method of solving I was familiar with. I sneaked a glance at the doctor. "Um… excuse me?" I said meekly.

Dr. Gaster crossed his arms. "Yes?"

I placed the papers on the table and pointed to the middle of page three. "This equation," I began. "I believe this number was divided incorrectly, the one in the parentheses next to the letter X." The doctor's brows furrowed and he leaned over, placing both his bony hands on the desk. Still standing, he peered over the pages. "Isn't that supposed to come out as two hundred instead of two hundred and seven?" I added quietly.

He studied it for some time. I twiddled my fingers nervously, hoping I hadn't gotten something wrong. I was quite sure there was a mistake in that equation, but I _was_ talking to the greatest scientist in all of the Underground. Perhaps it was _me_ who had made a mistake and not him.

Suddenly his eye sockets widened and he stood straight up. I looked at him to find he was returning my own quizzical expression with one of surprise. A hint of a smile touched his mouth. "Well, would you look at that," he said. "There _was_ a mistake in my calculations." He reached out his hand. "Mr. Amin, thank you for catching that. Otherwise, its end result may have been rather disastrous."

I shook his hand, not really understanding what he was talking about. "Er… thank you," I murmured.

"You're hired, Mr. Amin."

My mouth dropped an inch or two. "R-really?" He… he was going to hire me on the spot? Just like that?

The doctor was full on smiling now. "Yes, how soon can you start?"

I smiled back. "As soon as you need me."

"Wonderful! Tell me, where do you currently live?"

"In Snowdin."

"Are you willing to commute to work?"

"For a few weeks, yes, but I'm hoping get a place closer and-"

"I'll have it arranged you get an apartment in Royal City itself."

I was completely taken aback. "Oh, you don't have to. I can-"

"Nonsense!" It was Asgore who spoke now. A large grin stretched across his face and he clapped me on the back, causing me to almost stumble forward. I wasn't sure he was fully aware of his own strength. "Dr. Gaster is impressed with you, Mr. Amin. I'll see to it you get your own place here just as Gaster wishes."

"Can you start tomorrow nine o'clock sharp?" asked Dr. Gaster.

A small smile crossed my face. "Of course! Thank you."

On my way out of the palace I ran into Captain Sasha who must have noticed I was grinning like a fool. "So, I take it the interview went well." She was standing poised and on guard just outside the palace gates, but she dropped her stern expression to smirk at me.

I bobbed my head. "Oh yes, it went fantastically!" I cried. "At first I wasn't sure I would get the job, but then Dr. Gaster handed me a stack of papers and..." I babbled on enthusiastically like a child recounting his first day of school to his mother. I hardly ever talked that much, but right now I couldn't shut up, and what was more, the captain didn't even look _bored_ as I spoke, unlike my brother back at home. The captain listened to me with what I interpreted was genuine interest.

As I finished my tale the captain chuckled and said, "I am very glad it was you the doctor chose as his assistant. It's been awhile since we've had a fresh face around here, not to mention it's great to see someone interested in science besides the doctor himself. He's really wanted to make more scientific advancements, but it's difficult with just one person. So few monsters express interest in his field. I look forward to working alongside you sometime."

I frowned. "But… you're not a scientist, are you?" I inquired.

She smiled before shaking her head and taking up a guarding stance once more. "No, but the captain of the Royal Guard does occasionally discuss important projects and scientific endeavours with the royal scientist."

I smiled back. "Well, I look forward to working with you then, Captain."

Waving goodbye, I started to leave, but stopped when I heard her call after me, "Call me Sasha!"

I nodded and turned to leave again, but not without calling back, "It was nice to meet you then, Sasha!"

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 **A/N: A quick disclaimer: I'm not a math expert. I had to research the math portion of this chapter and I apologize if there are any mathematic fanatics out there who think I wrote it wrong, but I tried my best. Please drop a review and let me know how it is so far!**


	3. Breaking the Ice

**A/N: I finally sat down and got this chapter out after much procrastination. The plot's starting to pick up at the end. Enjoy! Please drop a review and let me know how it is!**

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 **Chapter 3: Breaking the Ice**

My apartment was small, but I couldn't have asked for anything better. It was on the second floor of a three floor building in Royal City (which has presently been renamed New Home, though I know not why). It had one living room, bath, kitchen, and a bedroom that doubled as my study. My bed stood against one side of the pale blue walls while my small wooden desk leaned against another corner with a bookcase to its left. As soon as I had obtained furniture I went around town buying any book I could get. My little library paled in comparison to Doctor Gaster's, but I was satisfied. The living room was the largest room in my apartment, big enough to hold a couch, armchair, and small table with three chairs. Still, the part of my apartment I cherished most highly was the balcony: small and simple it was with white stone railing. It was the perfect place to lean against the edge and feel the cool breeze that would draft in from tiny holes from the Surface.

I had occasionally wondered what the Surface was like, what humans were like. Our history painted them as vile creatures who hated monsters, but I could not judge for myself whether they were truly evil. After all, I had never met one and probably never would. Still, how fascinating it would be to meet one!

At first I had no clue what that diagram was that I had reviewed in the Doctor's study during my interview. Then it had been just a bunch of mathematical equations and calculations of nonsense. Not nonsense in the sense that I couldn't understand the calculations on the paper. In fact, I did understand them; I just had no clue what they were _for._ I soon found out.

It was for the Core: a huge system of mechanics and machinery and pathways so large it almost made my head spin. Even though it was complicated and full of unnecessary puzzles and obstacles, it was fantastically revolutionary! My mentor had come up with the greatest idea in all of the underground: the harnessing of electricity, and not just harnessing it, but creating it out of lava. I have no idea how, but Dr. Gaster discovered a way to convert molten rock into usable energy. When I asked him to explain it he launched into a long, complicated explanation of engineering and mechanics I could only partially follow. Eventually I gave up and contented myself with helping the doctor with the smaller calculations I knew how to do.

It was probably a week into my mentorship with Dr. Gaster when I finally became aware of what Gaster was building. Asgore was the one to accidentally let it slip. He came bursting into the large laboratory babbling something of success and asking how soon said "core" could be completed. My large eyes stared in confusion. Dr. Gaster, dressed in a long lab coat and turtleneck like he always was, gave the king a look so stern I would have never imagined anyone would dare give an expression such as _that_ to our ruler. He took it merely with a chuckle, however. "Oh, Gaster! You might as well tell him," he proclaimed. "Mr. Amin was bound to find out sooner or later. Besides, this idea you've had for years has been so fantastic. Why shouldn't we tell the Underground? Honestly I don't even know why you've wanted it kept quiet for so long."

At the time I had no idea why Gaster would keep something that large under wraps for so long, either. As I grew to know him I realized he was a very private, quiet person, and that I was one of the lucky few he had become comfortable enough around. He regarded his work in science as something almost sacred. It was his idea, his creative expression. He had moments of great humility that I wondered if he was at times embarrassed about sharing his work and ideas with others.

Still, Asgore insisted that I be informed of everything. Dr. Gaster had been developing the Core for some years now and I finally realized why a large piece of Hotland had been sectioned off since my childhood. Gaster had been building it for years. I had joined when the project was nearly completed, but it still had some kinks left to be sorted out. That's part of the reason why Gaster desired a helper. He wanted someone to look over his work. That, and Asgore later told me that the poor man had been spending so much time working and without sleep the king had insisted the scientist not share all this burden himself. Eager for work in the scientific field, I was more than happy to comply.

After six months of working with Dr. Gaster, the Core was finally completely and ready to be unveiled. King Asgore threw a huge party as an opening celebration. Everyone in the Underground showed up… at least, almost everyone. Queen Toriel had been invited, but failed to appear. King Asgore looked disappointed, but I dared not ask. Every monster knew something had happened between him and his wife, something shrouded in mystery. They had once had a child, too, two children actually. Interestingly enough one of them had been a human who had fallen into the Underground. Unfortunately, the two kids had passed away some time ago and Toriel left Asgore soon afterwards. It was a troublesome subject I had no desire to stir up, so I left the king to his own devices.

Adorned in a white suit, I was surrounded by countless strangers. Not much of a social man myself, I ended up hanging out mostly at the drinks table. A couple monsters said hello, but mostly I was left alone, that is, until I heard a voice call my name. "Fidel!"

I turned around to see a green monster walking toward me. At first I was very confused, but then I realized it was Sasha. My eyes widened even more than they naturally did. I had never seen her out of uniform before. Usually she was decked out in full armor, but now she didn't have anything but a royal blue dress and simple shoes. She was green and rather dinosaur-like, though her "skin" was not scaly, but looked tough like my own. A row of small spine-like ridges started on the middle of her forehead and traveled down to the tip of her tail. Her small snout held the expression of delight as she came toward me and she had one of her magic-manifested hands extended in greeting. "I thought that was you," she remarked with a smile.

My face felt mysteriously warm as I shook her hand. Clearing my throat, I tugged lightly on my collared shirt and returned her smile. "Nice to see you," I replied.

We fell into small talk, speaking of work, the latest gossip, the mundane things of life. She introduced me to her two fellow royal guards, Buck and Arlo. They were lizard-like and forest green in color. Unlike Sasha, they had scales and were a darker shade of green than she was. Very tall and dressed in identical tuxes, they towered over both me and Sasha, who was my height. They appeared serious and intimidating, but it was clear they respected their commander though she was much smaller than them. At the time I hadn't realized it, but eventually I discovered they were brothers. No wonder they looked so alike.

When I met them Buck and Arlo were discussing something in curious tones. "What are you boys discussing?" Sasha asked, butting into their conversation without a care of being polite. I had to admit, I admired her social bravery.

"We were just discussing who Doctor Gaster might be," said Buck in his gruff voice.

"He is a very mysterious fellow," agreed Arlo, whose voice was almost as gruff as his brother's, but not nearly so. Suddenly he raised his hand and pointed across the courtyard (Asgore hosted the party in the castle courtyard) to where a solitary Gaster was leaning against the wall watching everyone in silence. "Look at him over there. He's just standing there looming about. He won't even try making friends or even talking to anyone."

Sasha rolled her eyes. "He's just not very social," she explained. "Some monsters are like that. Why, I happen to know him rather personally and he's a fine young monster who's very sweet, if a bit awkward at times."

Buck was the one to speak next. "Where d'you suppose he came from? He just sort of appeared out of nowhere several years ago and suddenly he's the king's best friend."

"It _is_ very odd," Arlo added. Suddenly he turned to me. "What do you think, Mr. Amin? After all, you're his assistant. Has he ever shared his past with you?"

Three pairs of monster eyes were suddenly on me. "Well," I responded slowly. "I'm not sure. I haven't been working with him very long. He's very quiet and doesn't talk about much other than work, at least that's how he is with me."

The brothers' faces looked disappointed and they quickly changed the subject. I soon grew bored and could only stand there awkwardly talk about life in the Royal Guard. I was actually thinking of excusing myself when Sasha came to the rescue. "Let's go," she whispered to my earhole. "This conversation's getting dull."

Instead of going off someplace to talk like I expected, she actually pulled me onto the dance floor. Well, it was more like a circle carved out in the middle of the courtyard of monsters for those with a desire to dance, but we called it the dance floor just the same. A young male monster was playing the piano while a female was standing beside him singing her heart out. As I had never danced before, Sasha was the one to lead. It was a new experience for me, but enjoyable. We must have danced for an hour when suddenly she pulled me aside and informed me that she had to leave in order to get enough sleep for her job as Captain of the Royal Guard the next day.

When she left, I happened to bump into Doctor Gaster himself. "Oh, hello!" I said cheerfully.

"Hello," he said politely, but almost indifferently.

"Enjoying the party?" I tried to strike up a friendly conversation, but it was like pulling teeth.

"It's alright," was his quiet reply.

I blinked and stood in silence for a solid minute, not completely sure what to say. Finally I formulated a response, "Not a big fan of parties, I take it?"

"Not particularly."

"To be honest I'm not much of a party man myself. For goodness' sake, Sasha had to lead _me_ while we were dancing."

A small chuckle escaped the doctor.

I decided to be a little daring. "So, Doctor, what do you like to do in spare time?"

His eyebrows raised slightly. "I actually don't have much free time," he admitted. "Science is my job, my interest, and takes up much of my time, though I guess when I do have some spare time I read a little."

"What do you read?"

"Anything of science I can get my hands on."

"Sounds like science is everything to you." I chuckled lightly.

The doctor shrugged his shoulders. "Well, I used to be a salesman back when..." He suddenly trailed off and I didn't get to hear the end of his sentence.

I raised one brow. "Back when what?"

He shook his head. "Oh, nothing important."

This time it was me who shrugged my shoulders, "My father used to be a salesman actually," I remarked. "Before he passed away."

The doctor's eyes suddenly turned interested. "Did he?" he inquired.

We started speaking of sales-monsters and what they did. It was the first genuine conversation I had ever had with Doctor Gaster. We spoke for sometime and I finally came to see his perspective of the world. He asked me many questions about the monster world and I eventually decided he must have been a very isolated monster growing up. He seemed to actually know less than _me_ about some things of the Underground and I had hardly ever left Snowdin in my youth. Plus, he had a strange way of speaking, as if he wanted to say something but held back. Though I did get to better know his personality, he was still very shrouded in mystery.

The most interesting phase of my life began two years after I was employed by the doctor. In two years' time I was calling him "Gaster" instead of "Doctor" or "Doctor Gaster." In two years' time I had become very good friends with both Gaster and Sasha. In two years' time the Core had taken off and every monster was thrilled about this new thing called "electricity." In just two years' time there came a day when we received the shocking news that, at the time, I had no idea was about to turn my world, Gaster's world, and to a lesser extent Sasha's world, upside down.

What was the news? Humans had appeared in the Underground for the first time in years.


	4. The Humans

**I FINALLY got this written. Apologies for anyone following this story. I lost motivation for several months but I am finally starting to get into this again :)**

 **If anyone's interested, I drew a picture of what Sasha looks like on DeviantART and will hopefully be drawing Fidel, soon, and possibly various future scenes in this fic. My username on dA is "Soda-Fiz" and I'd love it if anyone reading this checked it out.**

 **Please drop a review and let me know how it is! Reviews are a large part of what motivate me to write my stories on here.**

 **Also a HUGE thanks to PantryMonster who has reviewed every single chapter so far. And to answer the question I totally forgot about that you asked awhile back: Yes, Sasha is the equivalent of Jordan.**

* * *

 **Chapter 4: The Humans**

I handed Gaster his daily coffee as I walked into the lab, greeted by the pale green walls of the lab and its light blue floor. The air conditioning was evident when I left the muggy heat of Hotland behind and felt the cool laboratory air on my skin. As I was originally from Snowdin, I preferred cooler temperatures.

Gaster took the coffee with a smile. "Ah, thank you so much, Fidel," he said with the daily cheer he now greeted me with everyday. After working with him for two fine years, it was now so routine to see him in either a white lab coat or a light turtleneck sweater and khaki slacks. He barely wore black anymore, a color I often saw on him the first few times we encountered each other.

If I were told that in just a couple years I would become Gaster's best friend, I probably would have given them a polite smile and silently disagreed. And yet here we were drinking coffee and doing working like two old chaps who'd known each other for decades. Gaster was, though at first a little distant, actually a very kind fellow with a sense of humility and endearing awkwardness about him. He was so tall that at times he seemed too clumsy for his own good. Many a time I found myself cleaning up spilled coffee or fluttering papers he managed to drop.

It was a fine warm day like it always was in Hotland when Sasha burst into the lab. Her armored steps went _clunk clunk_ as she ran toward us. She was breathing heavily. "G-Gaster! The king... wants to see you... right away," she wheezed. "It's of utmost importance, so please... drop any work you're doing and go immediately."

"Alright, Sasha," was Gaster's calm, but serious reply. "Where is he?"

"In the study. Quickly now, he's extremely anxious about the topic at hand. He'll explain everything when you get there."

In a flash Gaster nodded and was out the sliding doors headed toward New Home, formerly Royal City. An awkward silence hung between Sasha and me as she caught her breath. Not a fan of unnerving silence, I finally decided to break the tension. "What's all the urgency?"

She turned to me and, using her green magic hands, removed her helmet. I observed beads of sweat gathered on her brow and just under her nose on her small green snout. Her expression was wide-eyed and serious. "You'll never believe this," she began. "But one of my guards found humans near the Ruins."

At first I thought she was joking, so I didn't immediately respond. I waited for her to respond with a punch line, but nothing came. I gawked. " _Humans?_ "

Her expression remained unchanged and I knew for certain she was not playing a joke. "Yes, humans," she deadpanned. "Three of them, a family actually: a man, woman, and a child. When my guard informed me, I immediately told Asgore." She suddenly leaned in close to me and continued to speak with a lowered voice. I hoped she didn't see the blush that formed on my face when she drew near.

"I technically shouldn't be telling anyone this," she whispered. "But I trust you, Fidel, and you should learn of this sooner or later. The truth that many monsters don't know is that there have actually been other humans since the king's adopted child who have fallen into the Underground, but not in a long time. In fact, the last time they came was before Asgore employed Gaster. Before I became Captain of the Royal Guard, the captain before me worked closely with Asgore gathering several human souls in order to destroy the barrier. They managed to collect five before I was captain. Asgore just needs two more."

Her eyes snapped alert and her tone gained a hint of excitement. "Just think, we have three human souls at our disposal now. Then Asgore can take them and finally destroy the barrier!" Her voice grew excited, eyes sparkling with a charming delight I rarely saw in her. She was always so serious that it was a nice change from her usual stoic demeanor. Never would I have admitted it out loud, but I found her expression very charming and, dare I say... _attractive_.

I suddenly realized my mouth was hanging open like a fish. "What…?" I began. "You mean… you're telling me that Asgore's been hoarding human souls for _years_ now?

She nodded with a grin. " _Three_ _human souls._ It's even more than we need. We'll finally be free! Oh Fidel, I never thought that I would ever encounter a human in my lifetime, but here they are!"

"But… what are humans like?" I wondered. "Are they as cruel as the history books say they are?" I wouldn't say it aloud, but the idea of my own king hoarding potentially innocent souls, even human ones, just didn't settle well with me. It just seemed so unlike Asgore. He was always so kind and jolly. I couldn't imagine him even hurting a fly. Yes, history books said that humans were evil, but even I had come across some monsters who weren't all too nice.

Before Sasha could respond the doors slid open and from my peripheral I saw Gaster enter the lab. I jumped back at the sudden realization of how close I was to the captain. Straightening her stance, she turned to my mentor expectantly. "It's all sorted out," Gaster informed her. "I will be over to see the subjects shortly. I just need to get my things first."

Sasha dipped her head in a respectful nod. "I will go make sure they're ready then." She turned toward me with her outstretched hand of green magic, a hint of a smile on her face. Returning the smile, I took her hand, ready to shake it goodbye.

We did shake hands… at first. As I was about to let go her grip suddenly tightened on mine and she pulled me closer. Before I knew what happened she had planted her lips on my cheek before pulling away in record time. My face grew warm, _extremely_ warm. With a wink Sasha turned and marched out of the room as if nothing unusual had occurred. "See you soon, Fidel," she called.

There was silence as my brain tried desperately to process what had just happened. _Had… had she just kissed me?_ Did we start a relationship I didn't remember? We were certainly very friendly these past two years, but I couldn't recall anything romantic happening. Not publicly at least. I had daydreamed something of that sort happening a few times, but I would have never admitted to it out loud.

Someone chuckled. I was snapped from my thoughts, almost certain my face was a dark shade of scarlet. "Your pupils are so small I can barely see them," said a familiar voice beside me. _Gaster._ Oh no, I had completely forgotten he was there.

"I… I-I'm not exactly sure what that was," I spluttered. _Had the air conditioning broke?_ I rubbed the back of my neck.

My friend let out another chuckle. "I was wondering who was going to take the first step."

My mouth dropped like a fish for the second time that hour. " _What?_ What steps? What are you talking about?"

"You're both very taken with each other," Gaster remarked. "It's obvious. It's been obvious for the last two years."

I was certain my eyebrows had at this point reached the top of my forehead. "It's been obvious to _who?_ "

"Well, everyone."

" _Everyone?_ "

"I believe so. Me, Asgore, the guards..."

"Oh..." My shoulders slumped. _Well, if everyone knows, then there's no use denying it._ "Alright, yes," I admitted. "I am very taken with her, but are you sure the feeling is mutual?"

A teasing grin settled on the doctor's face. "I know it is," was his reply. "In fact, she told me herself." I turned away, still quite bashful, but Gaster laughed and nudged my shoulder. "Why do you think she stops by to 'check in on things' almost every day? It's not to see me, I know that. While our work does occasionally cross paths, she never used to visit me this often before you came along."

 _Alright, time to change the subject._ "Anyway..." I drawled. "Shouldn't we be going to see the humans?"

This time it was Gaster who looked surprised, though not nearly as much as I had been just seconds before. "She told you?"

"Oh, I'm sorry. I didn't-"

The doctor put up his hand. "No, no, it's alright. If anyone were to know besides Sasha, Asgore, and myself, I would rather it be you. I trust you."

I couldn't help a slight smile touch my face. It was a nice feeling, the feeling of having not only one, but two dear friends who placed their trust in me.

"But..." The skeleton's voice suddenly became serious. "This _must_ be kept between the king, the captain, and we scientists. There haven't been humans in the underground for years and it could cause unrest among the other monsters."

"Of course." Though I agreed, an air of uneasiness still lingered in the back of my mind.

Gaster picked up his clipboard and a pen. Tucking the latter into his coat pocket, we left the nice cool air of the lab behind. I shifted in my lab coat uncomfortably as we ventured through the dry, rocky scenery. Sweat began to gather on my bald head and behind my neck.

We made our way from Hotland to New Home where the humans were apparently being kept in the castle dungeon. The charming River person sang us a lovely song about the wet water and swishing of the waves. The moist but colder air of the river was a pleasant change from the air heated by lava itself.

The palace was as grand as always. We entered through the courtyard where we were led through corridors and into the dungeon. The dungeon was not nearly as bad as I was imagined. A few wooden cell doors lined a hallway. The walls were stone and the air smelled rather musty, but it wasn't unbearable. Were I a criminal, I would not have minded staying in this dungeon.

The first cell held the man. As we entered through the creaky door I was surprised to see Sasha there. Her back was to us, her tail slightly raised on alert. Her metal armor was clinking slightly and I soon realized she was _shaking._ I turned my eyes to the human.

He was the strangest creature I had ever seen. Taller than me by many inches, his height was almost that of Gaster's. He was on the muscular side, but he didn't appear to be a professional wrestler or anything of that sort. Thick brown hair grew from his head. It appeared to have at one point been combed down, but was now unkempt. A dirty, stained white button up shirt and black pants were what he wore. Brown stubble dotted his chin. Oh, but his skin was so pink and _pale_. Did humans always look this gaunt? Bluish circles were gathered under his wild brown eyes.

When I saw his chains I realized why Sasha had been shaking. The human was bound to the wall, but he was struggling. The captain's posture was squared and her whole body rigid as she use her magic hands to keep him pinned to the wall.

"What now?" the human spat. His voice was rough, dark, and dangerous. I shuddered to think what might happen if he were loose. The look in his eyes was not a friendly one. In fact, it seemed to have a desire to _hurt_ something. Instinctively I backed up to stand behind Sasha and beside Gaster. Though I knew every monster had magic, I was not skilled with my own and would be defenseless against an attacker. I hoped Sasha had the strength to keep him where he was. Perhaps they were true, the stories that claimed humans were full of cruelty and void of compassion.

"I don't know where you took them." The human growled, now looking at me and Gaster. "But if you so much as lay a _finger_ on my wife or son, I swear I will repay you ten times over. We're not science experiments to be poked and prodded! I've heard of you monsters. There have been stories and I thought they were all folktales, but apparently not."

" _Stop talking_ ," Sasha commanded, much sterner than I had ever heard her speak before.

Gaster spoke next. His voice was calm and unintimidated. "William, we're not here to hurt you. We just want to examine you and your family. Can you blame us for being curious? We haven't seen humans down here in a long time."

This "William," as he was called, refused to tell us anything, no matter how much Gaster questioned him. After what I guessed had been at least an hour, the doctor sighed and decided to try questioning the other two. William vehemently refused to let us see them. He hurled threats and curses I would rather not repeat at us, but of course he was powerless.

We entered the other cell, the one with the woman and child. I was the first to enter. The woman was huddled against the wall, cradling what I assumed was her child, the son. As I entered her head whipped up to look at me with blue, terrified eyes. Curly blond, yet dirty hair hung down her face in messy ringlets. She was not chained and neither was her little boy.

Her son was on the chubby side. He had her same blue eyes and blond hair, but his was straight instead of curly. Also frightened, he clung to his mother as if his life depended on it.

I stared at them in shock. They were so timid and forlorn. The man had been scary and aggressive, while these two were just sad and appeared to frightened of _me,_ and I had never been a very large monster. Though the woman was hunched on the floor in her ragged blue dress, I was sure that if she were standing she'd be taller than myself.

At that moment I heard a loud clatter behind me. Turning around, I was surprised to see Gaster standing at the door with an expression of pure shock. He had dropped his clipboard and pen. They lay scattered at his feet, papers spilled on the floor.

But Gaster wasn't staring at me in surprise. No, he was staring at the humans, the woman and her child.


End file.
